1. Field of the Invention
Aspects of the present invention are directed to an apparatus for use in sample monitoring.
2. Description of the Background
For the continuous emissions monitoring of oxygen on a hot wet basis for the power utility industry, the zirconium oxide sensor is commonly used. Such a sensor can either be placed directly in a stack and be used for in-situ monitoring of the oxygen therein on a hot wet basis or used as part of an extractive method for use in an extractive measurement system. In such an extractive method, an exhaust sample is transported from the stack using a heated sampling system to an oxygen sensor.
When the sample is monitored using an extractive measurement system, it is critical that the temperature of the sample in and around the sensor be stably maintained by heated components of the system and that no condensation of moisture in the sample occurs. If the temperature of the sample in and around the sensor is not stable, the oxygen measurements will be performed inaccurately. At the same time, the heated components of the extractive measurement system must not pose a risk of, e.g., fire or burn damage, to the operator.
It has been seen, however, that current extractive measurement systems may not reliably maintain the temperature of the sample in and around the sensor and also fail to sufficiently protect the operator. Indeed, in some current systems, a sensor box is heated via trace wiring and includes a heated pump that may be heated to a temperature that could uncontrollably exceed a performance rating for the wiring. Moreover, an exterior of the sensor box can also be heated to an extreme degree and thereby pose a danger to the operator.